This invention relates to an improved method and apparatus for providing information to a fork lift truck operator regarding the vertical position of forks of the truck, the height to which the forks can be raised for a given load and the speed of the truck by means of a display and an audible alarm.
Fork lift trucks, such as rider reach lift trucks, are often provided with a placard or plate on which capacity information is placed, e.g., information as to how high the forks may be raised with various loads on the forks. A capacity plate may include a table which states load weight versus recommended fork height indicating for a given truck that a load of 2500 pounds may be lifted to a recommended maximum height of 321 inches, a load of 3000 pounds may be lifted to a recommended maximum height of 300 inches, a load of 4000 may be lifted to a recommended maximum height of 270 inches, and so forth. It is apparent that such information can be used by the operator to determine heights to which a given load can be lifted and/or load size which can be lifted to a given height. The center of the load is also an important consideration. For example, if a load is moved from 24 inches forward of the mast to 34 inches forward of the mast, the load capacity may be reduced from 3000 pounds to 2100 pounds.
There is a need for a more convenient, attention getting, way of providing an operator with the information necessary to operate a fork lift truck to assist the operator in estimating or determining the weight of the load, the height of the forks and the speed of the truck.